EP2087019B1 - Hydrophobically modified cationic copolymers - Google Patents

Description

The present invention relates to a copolymer, a process for its preparation, the use of the copolymer, and a polymeric mixture and their use.

In non-flowable building material systems, water-soluble nonionic derivatives of polysaccharides, in particular cellulose and starch derivatives, are frequently used as rheology modifiers and water retention agents in order to delay or undesirably evaporate the undesired evaporation of the water required for hydration and processability into the substrate prevent. In plasters, adhesive mortars, fillers and joint fillers, but also in shotcrete for tunneling and in underwater concretes, water retention is controlled with such additives. As a result, such additives also have a decisive influence on the consistency (plasticity), smoothness, segregation, stickiness, adhesion (to the substrate and the tool), stability and Abrutschwiderstand and Haftzug- and compressive strength or shrinkage.

In the US-B-6,187,887 as well as in the US-A-2004/024154 are described high molecular weight sulfo-containing polymers that show good water retention properties. These polymers have in common that they are polyelectrolytes with a net anionic charge.

However, an important property of the additives in tile adhesives and plasters is also the thickening in the presence of elevated salt concentrations.

The polymers according to US-B-6,187,887 show under such conditions a drastic decrease in thickening, while additives according to US-A-2004/024154 in the presence of elevated salt concentrations are relatively stable.

In the case of high-performance tile adhesives, for example, the aim is to set particularly short curing times in order to ensure early accessibility (about 5 hours) of the laid tiles even at low temperatures (approx. 5 ° C). This is achieved by extremely high dosages of salts acting as accelerators, for example calcium formate. In the case of the use of such high salt loads (in particular divalent cations are critical) and the polymers in accordance with US-A-2004/024154 much of their effectiveness.

In that regard, there is a certain need to formulate such high performance tile adhesives with water soluble nonionic derivatives of polysaccharides, especially cellulose ethers, as water retention agents. However, this entails a number of disadvantages for the user, which is due to the fact that cellulose ethers have low thermal flocculation points, which ultimately causes the water retention capacity at temperatures above 30 ° C drastically weaker. Cellulose ethers moreover tend, especially in relatively high dosages, to high tackinesses, which disadvantageously have to be alleviated by the addition of further formulation components.

In addition to the anionic polymers described above, it is also possible to use cationic copolymers:

The US 5,601,725 describes hydrophobically modified copolymers of diallyldimethylammonium chloride with dimethylaminoethyl acrylate or methacrylate, which have been quaternized with benzyl or cetyl chloride. The hydrophobic group is thus contained in the same monomer unit carrying the cationic charge. This is also the case in the US 5,292,793 described hydrophobically modified, water-soluble cationic copolymers of the case. These are copolymers of acrylamide with a cationic monomer derived from dimethylaminoethyl methacrylate or methacrylate which has been quartenized with an alkyl halide (C ₈ to C ₂₀ ). In the US 5,071,934 hydrophobically modified copolymers are described which act as efficient thickeners for water and saline solutions. These are copolymers of acrylamide with a cationic monomer which is derived from dimethylaminopropyl methacrylamide, the with an alkyl halide (C ₇ to C ₂₃₎ was quaternized.

All listed cationic copolymers have in common that they cause a thickening effect due to the hydrophobic alkyl group in water and in weakly saline solutions, but do not ensure sufficient thickening in building material systems with high salt load. Also, these show in building material systems both at low, as well as high salt load insufficient water retention properties.

It is known that cationic polyelectrolytes interact intensively with oppositely charged surfactants. So be in the US-A-2004/209780 cationically modified polysaccharides and anionic surfactants described as an additive to fracturing fluids. Here, the effect is exploited that polyelectrolytes interact strongly with oppositely charged surfactants via electrostatic attractive forces. In addition, the hydrophobic groups of the surfactants thus bound to the polymer have associatively effective thickening effects. The interactions become even more complex, although the polyelectrolyte has covalently attached to the main chain, hydrophobic groups.

However, these hydrophobically modified cationic copolymers, even in combination with anionic surfactants in building material systems, do not show adequate thickening and completely inadequate water retention properties.

It is an object of the present invention to provide copolymers as water retention agents and rheology modifiers for aqueous building material systems which do not have the disadvantages mentioned even in the case of high salt loads.

• i) 5 bis 60 Mol-% einer Struktureinheit a),
• ii) 20 bis 80 Mol-% einer Struktureinheit b) und
• iii) 0,01 bis 3 Mol-% einer Struktureinheit c),

wobei die Struktureinheit a) durch folgende allgemeine Formel (I) repräsentiert wird:

worin

R¹

gleich oder verschieden ist (d.h. R¹ kann auch innerhalb eines Copolymers variieren)und durch Wasserstoff und/oder einen Methylrest repräsentiert wird,

R² und R³

jeweils gleich oder verschieden sind und unabhängig voneinander jeweils durch Wasserstoff, einen aliphatischen Kohlenwasserstoffrest mit 1 bis 20 C-Atomen (verzweigt oder unverzweigt, bevorzugt Methyl-, Ethylrest), einen cycloaliphatischen Kohlenwasserstoffrest mit 5 bis 8 C-Atomen (insbesondere Cylohexylrest) und/oder einen Arylrest mit 6 bis 14 C-Atomen (insbesondere Phenylrest), repräsentiert werden,

R⁴

gleich oder verschieden ist und durch einen mit R² oder R³ identischem Substituenten, -(CH₂)_x-SO₃M_k,

und/oder

repräsentiert wird,

M

gleich oder verschieden ist und durch ein ein- oder zweiwertiges Metallkation, Ammoniumkation (NH₄ ⁺) und/oder quarternäres Ammoniumkation (NR₁R₂R₃R₄)⁺,

k

gleich oder verschieden ist und durch ½ und/oder 1 repräsentiert wird,

Y

gleich oder verschieden ist und durch Sauerstoff, -NH und/oder - NR², repräsentiert wird,

V

gleich oder verschieden ist und durch -(CH₂)_x-, , und/oder , repräsentiert wird,

x

gleich oder verschieden ist und durch eine ganze Zahl von 1 bis 6 (bevorzugt 1 oder 2) repräsentiert wird,

X

gleich oder verschieden ist und durch ein Halogenatom (bevorzugt Ci oder Br), C₁- bis C₄-Alkylsulfat (bevorzugt Methylsulfat) und/oder C₁-bis C₄-Alkylsulfonat (bevorzugt Methylsulfonat), repräsentiert wird,

die Struktureinheit b) durch folgende allgemeine Formeln (IIa) und/oder (IIb) repräsentiert wird:

worin

Q

gleich oder verschieden ist und durch Wasserstoff und/oder -CHR²R⁵ repräsentiert wird,

R¹, R² und R³

jeweils mit der Maßgabe die vorstehend genannten Bedeutungen haben, dass im Falle von Q ungleich Wasserstoff R² und R³ in der allgemeinen Formel (IIb) zusammen für eine -CH₂-(CH₂)_y- Methylengruppe stehen können, so dass die allgemeine Formel (IIb) gemäß folgender Struktur vorliegt:

mit

R5

gleich oder verschieden, sowie repräsentiert durch ein Wasserstoffatom, einen C₁- bis C₄-Alkylrest, eine Carbonsäuregruppe und/oder eine Carboxylatgruppe -COOM_k, wobei y gleich oder verschieden ist und durch eine ganze Zahl von 1 bis 4 (bevorzugt 1 oder 2) repräsentiert wird, sowie M und k jeweils die vorstehend genannten Bedeutungen haben,

die Struktureinheit c) durch die allgemeinen Formel (III) repräsentiert wird:

worin

U

gleich oder verschieden ist und durch -COO(C_mH_2mO)_n-R⁶, und/oder -(CH₂)_p-O(C_mH_2mO)_n-R⁶ repräsentiert wird,

m

gleich oder verschieden ist und durch eine ganze Zahl zwischen 2 und 4 (bevorzugt 1 oder 2) repräsentiert wird,

n

gleich oder verschieden ist und durch eine ganze Zahl zwischen 1 und 200 (bevorzugt 1 bis 20) repräsentiert wird,

p

gleich oder verschieden ist und durch eine ganze Zahl zwischen 0 und 20 (bevorzugt 1 bis 5) repräsentiert wird, R⁶ gleich oder verschieden ist und durch

(im Falle von z=3: bevorzugt (R⁷)_z am Aromaten in den para- und ortho-Positionen) repräsentiert wird,

R⁷

gleich oder verschieden ist und durch Wasserstoff, eine C₁- bis C₆-Alkylgruppe (unverzweigt oder verzweigt, bevorzugt Methyl- oder Ethylgruppe), und/oder eine Arylalkylgruppe mit C₁- bis C₁₂-Alkyl-(unverzeigt oder verzweigt, bevorzugt Methyl-, Ethyl-) sowie C₆- bis C₁₄-Arylrest (bevorzugt Styrylrest) repräsentiert wird,

z

gleich oder verschieden ist und durch eine ganze Zahl zwischen 1 und 3 (bevorzugt 3) repräsentiert wird (z gibt an, wieviele R⁷ an dem Phenylrest gebunden sind)und

R¹

die vorstehend genannte Bedeutung hat.

The solution to this problem is a copolymer comprising

• i) 5 to 60 mol% of a structural unit a),
• ii) 20 to 80 mol% of a structural unit b) and
• iii) from 0.01 to 3 mol% of a structural unit c),

wherein the structural unit a) is represented by the following general formula (I):

wherein

R ¹

is the same or different (ie R ¹ can also vary within a copolymer) and is represented by hydrogen and / or a methyl radical,

R ² and R ³

in each case identical or different and independently of one another by hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms (branched or unbranched, preferably methyl, ethyl radical), a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms (in particular cylohexyl radical) and / or an aryl radical having 6 to 14 C atoms (in particular phenyl radical),

R ⁴

is identical or different and is replaced by a substituent identical to R ² or R ³ , - (CH ₂ ) _x -SO ₃ M _k ,

and or

is represented,

M

is the same or different and is replaced by a monovalent or divalent metal cation, ammonium cation (NH ₄ ⁺ ) and / or quaternary ammonium cation (NR ₁ R ₂ R ₃ R ₄ ) ⁺ ,

k

is the same or different and is represented by ½ and / or 1,

Y

is the same or different and is represented by oxygen, -NH and / or - NR ² ,

V

is the same or different and is represented by - (CH ₂ ) _x - _,, and / or,

x

is the same or different and represented by an integer from 1 to 6 (preferably 1 or 2),

X

is the same or different and are a halogen atom (preferably Cl or Br), C ₁ - to C ₄ alkyl sulfate (preferably methyl sulfate), and / or C ₁ to C ₄ alkyl sulfonate (preferably methyl sulfonate) is represented,

the structural unit b) is represented by the following general formulas (IIa) and / or (IIb):

wherein

Q

is the same or different and is represented by hydrogen and / or -CHR ² R ⁵ ,

R ¹ , R ² and R ³

in each case with the proviso have the meanings given above, that in the case of Q other than hydrogen R ² and R ³ in the general formula (IIb) together may stand for a -CH ₂ - (CH ₂ ) _y - methyl group, so that the general Formula (IIb) according to the following structure:

With

R5

the same or different and represented by a hydrogen atom, a C ₁ - to C ₄ -alkyl radical, a carboxylic acid group and / or a carboxylate group -COOM _k , where y is the same or different and is an integer from 1 to 4 (preferably 1 or 2), and M and k are each as defined above,

the structural unit c) is represented by the general formula (III):

wherein

U

is the same or different and is represented by -COO (C _m H _2m O) _n -R ⁶ , and / or - (CH ₂ ) _p -O (C _m H _2m O) _n -R ⁶ ,

m

is the same or different and represented by an integer between 2 and 4 (preferably 1 or 2),

n

is the same or different and represented by an integer between 1 and 200 (preferably 1 to 20),

p

is the same or different and represented by an integer between 0 and 20 (preferably 1 to 5), R ^{6 is the} same or different and is represented by

(in the case of z = 3: preferably (R ⁷ ) _{z is represented} on the aromatic in the para and ortho positions),

R ⁷

is the same or different and is hydrogen, a C ₁ - to C ₆ alkyl group (unbranched or branched, preferably methyl or ethyl group), and / or an arylalkyl group having C ₁ - to C ₁₂ alkyl (straight or branched, preferably Methyl, ethyl) and C ₆ - to C ₁₄ -aryl (preferably styryl) is represented,

z

is the same or different and is represented by an integer between 1 and 3 (preferably 3) (z indicates how many R ^{7 are} attached to the phenyl radical) and

R ¹

has the abovementioned meaning.

By means of these copolymers according to the invention, considerable improvements in water retention in aqueous building material systems based on hydraulic binders, such as cement, lime, gypsum, anhydrite, etc., can also be achieved in the case of high salt loads. Depending on the composition of the copolymers, the rheology modification, the water retention capacity, the stickiness and the processing profile can be set optimally for the respective application.

The good water solubility required for the use of the copolymer according to the invention in aqueous building material applications is ensured in particular by the cationic structural unit a). The neutral structural unit b) is needed mainly for the construction of the main chain and the achievement of the appropriate chain lengths, whereby the hydrophobic structural units c) allow an associative thickening, which is advantageous for the desired product properties.

The structural unit a) is preferably derived from the polymerization of one or more of the monomer species [2- (acryloyloxy) ethyl] trimethylammonium chloride, [2- (acryloylamino) ethyl] trimethyl ammonium chloride, [2- (acryloyloxy) ethyl] trimethyl ammonium methosulfate, [2- (methacryloyloxy) ethyl] trimethyl ammonium chloride or methosulfate, [3- (acryloylamino) propyl] trimethyl ammonium chloride, [3- (methacryloylamino) propyl] trimethyl ammonium chloride, N- ( 3-sulfopropyl) -N-methyacryloxyethyl-N'-N-dimethyl-ammonium betaine, N- (3-sulfopropyl) -N-methyacrylamidopropyl-N, N-dimethyl-ammonium-betaine and / or 1- (3-sulfopropyl ) -2-vinyl-pyridinium-betaine.

It is in principle feasible to replace up to about 15 mol% of the structural units a) by further cationic structural units derived from N, N-dimethyl-diallyl-ammonium chloride and N, N-diethyl-diallyl-ammonium chloride.

In general, the structural unit b) is derived from the polymerization of one or more of the monomer species acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-ethylacrylamide, N-cyclohexylacrylamide, N-benzylacrylamide, N-methylolacrylamide, N-tertiary butylacrylamide, etc. Examples of monomers as the basis for the structure (IIb) are N-methyl-N-vinylformamide, N-methyl-N-vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam and / or N- Vinylpyrrolidone-5-carboxylic acid, forth.

Most of the structural unit c) is derived from the polymerization of one or more of the monomer species tristyrylphenol polyethylene glycol 1100 methacrylate, tristyrylphenol polyethylene glycol 1100 acrylate, tristyrylphenol polyethene glycol 1100 monovinyl ether, tristyrylphenol polyethylene glycol 1100-vinyloxy-butyl ether and / or or tristyrylphenol polyethylene glycol block propylene glycol allyl ether.

In a preferred embodiment of the invention, the structural units a) are present in the copolymer at 15 to 50 mol%, b) at 30 to 75 mol% and c) at 0.03 to 1 mol%.

worin

Z

gleich oder verschieden ist und durch -COO(C_mH_2mO)_n-R⁸ und/oder -(CH₂)_p-O(C_mH_2mO)_n-R⁸, repräsentiert wird,

R⁸

gleich oder verschieden ist und durch Wasserstoff und/oder C₁- bis C₄-Alkyl (verzweigt oder unverzweigt, bevorzugt Methyl-, Ethyl-) repräsentiert wird, sowie

R¹, m, n und p

die jeweils vorstehend genannten Bedeutungen haben.

In most cases, the copolymer described above contains up to 5 mol%, preferably 0.05 to 3 mol% of a structural unit d), which is represented by the general formula (IV):

wherein

Z

is identical or different and is represented by -COO (C _m H _2m O) _n -R ⁸ and / or - (CH ₂ ) _p -O (C _m H _2m O) _n -R ⁸ ,

R ⁸

is identical or different and is represented by hydrogen and / or C ₁ - to C ₄ -alkyl (branched or unbranched, preferably methyl, ethyl), as well as

R ¹ , m, n and p

each have the meanings given above.

In general, the structural unit d) from the polymerization of one or more of the following monomer species allyl polyethylene glycol (350 to 2000), methyl polyethylene glycol (350 to 3000) monovinyl ether, polyethylene glycol (500 to 5000) -vinyloxy-butyl ether, polyethylene glycol-block-propylene glycol (500 to 5000) -vinyloxy-butyl ether, methylpolyethylene glycol block propylene glycol allyl ether, methyl polyethylene glycol 750 methacrylate, polyethylene glycol 500 methacrylate, methyl polyethylene glycol 2000 monovinyl ether and / or Methyl polyethylene glycol block propylene glycol allyl ether.

Copolymers of the invention containing the structural unit d) give the building material a further improved creaminess, which is advantageous for the processor.

worin

W

gleich oder verschieden ist und durch -CO-O-(CH₂)_x- und/oder -CO-NR²-(CH₂)_x- repräsentiert wird, sowie

Frequently, the copolymer according to the invention contains up to 40 mol%, preferably 0.1 to 30 mol%, of a structural unit e) which is represented by the general formula (V):

wherein

W

is the same or different and is represented by -CO-O- (CH ₂ ) _x - and / or -CO-NR ² - (CH ₂ ) _x -, as well as

R ¹ , R ² , R ³ and x each have the meanings given above. Usually, the structural unit e) is derived from the polymerization of one or more of the following monomer species [3- (methacryloylamino) -propyl] -dimethylamine, [3- (acryloylamino) -propyl] -dimethylamine, [2- (methacryloyl-oxy) -ethyl] -dimethylamine, [2- (acryloyl-oxy) -ethyl] -dimethylamine, [2- (methacryloyl-oxy) -ethyl] -diethylamine and / or [2- (acryloyl-oxy) -ethyl] -diethylamine.

By incorporating the structural unit e), the air-pore stability of the resulting copolymers is improved.

worin

S

gleich oder verschieden ist und durch -COOM_k repräsentiert wird, sowie

M, k und R¹

jeweils die vorstehend genannten Bedeutungen haben.

In many cases, the copolymer of the invention contains up to 20 mol%, preferably 0.1 to 10 mol%, of a structural unit f), which is represented by the general formula (VI):

wherein

S

is the same or different and is represented by -COOM _k , as well as

M, k and R ¹

each have the meanings given above.

In general, the structural unit f) from the polymerization of one or more of the following monomer species acrylic acid, sodium acrylate, methacrylic acid and / or sodium methacrylate, forth.

Copolymers which contain the structural unit f) show advantages in building material systems in which particularly short mixing times are necessary.

The number of repeating structural elements in the copolymer according to the invention is not limited and depends strongly on the respective field of application. However, it has proven advantageous to adjust the number of structural units so that the copolymers have a number average molecular weight of 50,000 to 20,000,000.

The copolymer according to the invention can obtain a slightly branched and / or slightly crosslinked structure by the incorporation of small amounts of crosslinker. Examples of such crosslinker components are triallylamine, triallylmethylammonium chloride, tetraallylammonium chloride, N, N'-methylenebisacrylamide, triethylene glycol bismethacrylate, triethylene glycol bisacrylate, polyethylene glycol (400) bismethacrylate, and polyethylene glycol (400) bisacrylate. These compounds should only be used in amounts that still contain water-soluble copolymers to be obtained. In general, the concentration will rarely exceed 0.1 mol%, based on the sums of the structural units a) to f) - however, a person skilled in the art can easily determine the maximum amount of crosslinker component that can be used.

The copolymers of the invention are prepared in a manner known per se by linking the structural units a) to f) (d) to f) in each case optionally) forming monomers by free-radical polymerization. Since the products according to the invention are water-soluble copolymers, the polymerization in the aqueous phase, the polymerization in the reverse emulsion or the polymerization in the inverse suspension are preferred. Appropriately, the preparation is carried out by gel polymerization in an aqueous phase.

In the case of the preferred gel polymerization, it is advantageous to polymerize at low reaction temperatures and with a suitable initiator system. The combination of two initiator systems (azo initiators and redox system), which are first thermally started photochemically at low temperatures and then due to the exothermicity of the polymerization, a conversion of ≥ 99% can be achieved. Other adjuvants, such as molecular weight regulators, e.g. As thioglycolic acid, mercaptoethanol, formic acid and sodium hypophosphite can also be used. The gel polymerization is preferably carried out at -5 to 50 ° C, wherein the concentration of the aqueous solution is preferably adjusted to 25 to 70 wt .-%. To carry out the polymerization, the monomers to be used according to the invention are expediently mixed in aqueous solution with buffers, molecular weight regulators and other polymerization auxiliaries. After setting the polymerization pH, which is preferably between 4 and 9, the mixture is purged with a protective gas such as helium or nitrogen and then the heating or cooling to the corresponding polymerization temperature. If the process is carried out in the form of an unstirred gel polymerization, it is polymerized in adiabatic reaction conditions in preferred layer thicknesses of 2 to 20 cm, in particular 8 to 10 cm. The polymerization is carried out by adding the polymerization initiator and Irradiation with UV light at low temperatures (between - 5 and 10 ° C) started. The polymer is using a release agent (eg. B. Sitren ^® Goldschmidt GmbH 595) comminuted after complete conversion of the monomers to accelerate through a larger surface drying. By the gentlest possible reaction and drying conditions crosslinking side reactions can be avoided, so that polymers are obtained which have a low gel content.

Depending on the mode of use, the preferred amounts used of the copolymers according to the invention are between 0.005 and 5% by weight, based on the dry weight of the building material system.

The dried copolymers are supplied in powder form for dry mortar applications (e.g., tile adhesives) to their inventive use. The size distribution of the particles should be selected by adjusting the grinding parameters as far as possible so that the average particle diameter is less than 100 microns (determination according to DIN 66162) and the proportion of particles with a particle diameter greater than 200 microns less than 2 wt .-% (determination according to DIN 66162). Preference is given to those powders whose mean particle diameter is less than 60 μm and the proportion of particles having a particle diameter greater than 120 μm is less than 2% by weight. Particular preference is given to those powders whose mean particle diameter is less than 50 μm and the proportion of particles having a particle diameter greater than 100 μm is less than 2% by weight.

The copolymer of the invention is used as an additive for aqueous building material systems containing hydraulic binders, in particular cement, lime, gypsum or anhydrite.

The hydraulic binders are preferably present as a dry mortar composition, in particular as a tile adhesive or gypsum plaster.

A further improvement of said properties can be achieved if the copolymer according to the invention is used together with an anionic surfactant as a mixture.

• α) das erfindugsgemäße Copolymer und
• β) ein anionisches Tensid, welches durch die allgemeine Formeln
  
          (VII)     J-K
  
  oder
  
          (VIII)     T-B-K
  
  repräsentiert wird,

wobei J und T jeweils den hydrophoben Teil des Tensids darstellt, K eine anionische funktionelle Gruppe ist, T einen hydrophoben Teil des Tensids darstellt und B eine Spacer-Gruppe ist, wobei

J

durch einen aliphatischen Kohlenwasserstoffrest mit 8 bis 30 C-Atomen (verzweigt oder unverzweigt, bevorzugt 8 bis 12 C-Atome), einen cycloaliphatischen Kohlenwasserstoffrest mit 5 bis 8 C-Atomen (insbesondere Cylohexyl-) oder einen Arylrest mit 6 bis 14 C-Atomen (insbesondere Phenyl) repräsentiert wird,

K

durch -SO₃M_k, -OSO₃M_k, -COOM_k, oder -OP(O)(OH)OM_k repräsentiert wird,

M und k

jeweils die vorstehend genannte Bedeutung haben,

T

durch einen aliphatischen Kohlenwasserstoffrest mit 8 bis 30 C-Atomen (verzweigt oder unverzweigt, bevorzugt 8 bis 12 C-Atome), einen cycloaliphatischen Kohlenwasserstoffrest mit 5 bis 8 C-Atomen (insbesondere Cylohexyl), einen Arylrest mit 6 bis 14 C-Atomen (insbesondere Phenyl) oder R⁶, repräsentiert wird,

B

durch -O(C_mH_2mO)_n- repräsentiert wird, sowie

K, R⁶, m und n

jeweils die vorstehend genannten Bedeutungen haben.

The invention thus also provides a polymeric mixture containing

• α) the erfindugsgemäße copolymer and
• β) an anionic surfactant represented by the general formulas
  
  (VII) JK
  
  or
  
  (VIII) TBK
  
  is represented,

wherein J and T are each the hydrophobic part of the surfactant, K is an anionic functional group, T is a hydrophobic part of the surfactant, and B is a spacer group, wherein

J

by an aliphatic hydrocarbon radical having 8 to 30 C atoms (branched or unbranched, preferably 8 to 12 C atoms), a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms (in particular cyclohexyl) or an aryl radical having 6 to 14 C atoms (in particular phenyl) is represented,

K

is represented by -SO ₃ M _k , -OSO ₃ M _k , -COOM _k , or -OP (O) (OH) OM _k ,

M and k

each have the meaning given above,

T

by an aliphatic hydrocarbon radical having 8 to 30 C atoms (branched or unbranched, preferably 8 to 12 C atoms), a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms (in particular cyclohexyl), an aryl radical having 6 to 14 C atoms ( in particular phenyl) or R ⁶ , is

B

is represented by -O (C _m H _2m O) _n -, as well as

K, R ⁶ , m and n

each have the meanings given above.

Preferably, the polymeric mixture comprises 80 to 99% by weight of the copolymer of the invention and 1 to 20% by weight of the above-described anionic surfactant.

The anionic surfactant according to the general formula (VII) is usually present as alkyl sulfonate, arylsulfonate, alphaolefinsulfonate, alkyl phosphate or fatty acid salt and the anionic surfactant of the general formula (VIII) usually as alkyl ether sulfate before.

It is also possible to use mixtures of the listed classes of anionic surfactants.

The polymeric mixture according to the invention has virtually the same application profile as the copolymer of the invention and is preferably used as an additive for aqueous building material systems containing hydraulic binders.

The copolymers and polymeric mixtures according to the invention may also each be used in combination with nonionic polysaccharide derivatives, such as methylcellulose (MC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), methylhydroxyethylcellulose (MHEC), methylhydroxypropylcellulose (MHPC), and welan gum and / or diutan Gum, to be used.

The following examples are intended to illustrate the invention in more detail.

Copolymer 1 (gel polymerization)

In a 2 1 three-necked flask equipped with stirrer and thermometer 296 g of water were submitted. Subsequently, 319 g (0.92 mol, 26.8 mol%) of [3- (acryloylamino) -propyl] -trimethylammonium chloride (60% by weight solution in water) (I), 355 g (2.5 mol, 73 mol%) of acrylamide (50 wt% solution in water) (II) and 19 g (0.0068 mol, 0.2 mol% of tristyrylphenol polyethylene glycol 1100-methacrylate (60 wt%). 50 mg of formic acid were added as molecular weight regulator, the solution was adjusted to pH = 7 with 20% strength sodium hydroxide solution, rendered inert with nitrogen for 30 minutes, and cooled to about 5 ° C. The solution was transferred to a plastic container of dimensions (b * t * h) 15 cm * 10 cm * 20 cm and then sequentially 150 mg of 2,2'-azobis (2-amidinopropane) dihydrochloride, 1.0 g of 1 % Rongalit C solution and 10 g of 0.1% tert-butyl hydroperoxide solution were added by irradiation with UV light (two Philips tubes, Cleo Performance 40 W). After about 2 hours, the hard gel was removed from the plastic container and cut with scissors into 5 cm × 5 cm × 5 cm gel cubes. Before the gel cubes were comminuted by means of a conventional meat grinder, they were coated with the release agent Sitren 595 (polydimethylsiloxane emulsion, Goldschmidt). The release agent is a polydimethylsiloxane emulsion which has been diluted 1:20 with water.

The resulting gel granules of copolymer 1 were uniformly distributed on a dry grid and dried in a circulating air dryer at about 90-120 ° C in vacuo to constant weight.

There were obtained about 375 g of a white, hard granules, which was converted by means of a centrifugal mill in a powdery state. The average particle diameter of the polymer powder of copolymer 1 was 40 .mu.m and the proportion of particles having a particle diameter greater than 100 .mu.m was less than 1 wt .-%.

Copolymer 2

According to copolymer 1, copolymer 2 was prepared from 48 mole% of [3- (acryloylamino) -propyl] -trimethylammonium chloride (I), 51.4 mole% of acrylamide (II), 0.3 mole% of tristyrylphenol polyethylene glycol 1100 methacrylate (III) and 0.3 mol% of polyethylene glycol (2000) -vinyloxy-butyl ether (IV). As molecular weight regulator, 80 ppm of formic acid was added.

Copolymer 3

According to copolymer 1, copolymer 3 was prepared from 38 mol% of [3- (methacryloylamino) -propyl] -trimethylammonium chloride (I), 61 mol% of acrylamide (II), 0.3 mol% of tristyrylphenol-polyethylene glycol 1100-methacrylate (III ) and 0.7 mol% of methylpolyethylene glycol (3000) monovinyl ether (IV). As a molecular weight regulator, 200 ppm of formic acid was added.

Copolymer 4

According to copolymer 1, copolymer 4 was 26 mole% of [2- (methacryloyloxy) ethyl] trimethylammonium chloride (I), 65 mole% of acrylamide (II), 0.2 mole% of tristyrylphenol polyethylene glycol 1100 methacrylate (III) and 8.8 mol% of [2- (methacryloyl-oxy) -ethyl] -diethylamine (V). As molecular weight regulator, 80 ppm of formic acid was added.

Copolymer 5

According to copolymer 1, copolymer 5 was 16 mol% of [3- (acryloylamino) -propyl] -trimethylammonium chloride (I), 56.8 mol% of acrylamide (II), 0.2 mol% of tristyrylphenol polyethylene glycol 1100-methacrylate (III) and 27 mol% of [3- (acryloylamino) -propyl] -dimethylamine (V). As molecular weight regulator, 40 ppm of formic acid was added.

Copolymer 6

According to copolymer 1, copolymer 6 was 27 mol% of [3- (methacryloylamino) -propyl] -trimethylammonium chloride (I), 55.6 mol% of acrylamide (II), 0.2 mol% of tristyrylphenol polyethylene glycol 1100 methacrylate (III), 0.2 mol% of polyethylene glycol-block-propylene glycol (1100) -vinyloxy-butyl ether (IV) and 17 mol% of [3- (methacryloylamino) -propyl] -dimethylamine (V) produced. As molecular weight regulator, 40 ppm of formic acid was added.

Copolymer 7

According to copolymer 1, copolymer 7 was 45.4 mol% of [3- (acryloylamino) -propyl] -trimethylammonium chloride (I), 48 mol% of acrylamide (II), 0.3 mol% of tristyrylphenol polyethylene glycol 1100 methacrylate (III), 0.3 mol% of polyethylene glycol-block-propylene glycol (3000) -vinyloxy-butyl ether (IV) and 6 mol% of acrylic acid (VI). As molecular weight regulator, 70 ppm of formic acid was added.

Copolymer 8

According to copolymer 1, copolymer 8 was 28 mol% of [2- (methacryloyloxy) ethyl] trimethylammonium chloride (I), 46.7 mol% of N, N-dimethylacrylamide (II), 0.3 mol% of tristyrylphenol polyethylene glycol-1100-methacrylate (III), 21 mol% of [3- (acryloylamino) -propyl] -dimethylamine (V) and 4 mol% of acrylic acid (VI). As molecular weight regulator, 30 ppm of formic acid was added.

Copolymer 9

According to copolymer 1, copolymer 9 was prepared from 25 mol% of [2- (methacryloyloxy) ethyl] trimethylammonium chloride (I), 57 mol% of acrylamide (II), 0.2 mol% of tristyrylphenol polyethylene glycol 1100 methacrylate (III), 0.2 mol% of polyethylene glycol-block-propylene glycol (2000) -vinyloxy-butyl ether (IV), 12 mol% of [3- (acryloylamino) -propyl] -dimethylamine (V) and 5.6 mol -% acrylic acid (VI) produced. As molecular weight regulator, 30 ppm of formic acid was added.

Polymer mixture 1

Consisting of 95 wt .-% of copolymer 3 and 5 wt .-% C ₁₄ / C ₁₆ -Alphaolefinsulfonat sodium salt (VII) (Hostapur OSB Fa. SE Tylose GmbH & Co. KG).

Polymeric mixture 2

Consisting of 85% by weight of copolymer 9 and 15% by weight of sodium lauryl sulfate (VII) (commercial product of F.B. Silbermann GmbH & Co. KG).

Comparative Polymer 1 / Comparative Example 1

According to US 5,292,793 Comparative polymer 2 was prepared from 20 mol% of [2- (methacryloyloxy) ethyl] dimethyl cetylammonium bromide and 80 mol% of acrylamide.

Comparative Polymer 2 / Comparative Example 2

According to US-A-2004/024154 Comparative Polymer 3 was 47.1 mol% of 2-acrylamido-2-methylpropanesulfonic acid, 49.1 mol% of acrylamide, 0.7 mol% of tristyrylphenol polyethylene glycol 1100 methacrylate and 3.1 mol% of 2- (methacrylamido ) -propyl] -trimethylammonium chloride.

applications

The performance evaluation of the copolymers and polymeric mixtures according to the invention was carried out using test mixtures from the field of stable tile adhesive mortar and gypsum plaster.

- Tile adhesive mortar:

For this purpose, it was tested in practice using a ready-to-use dry mixture to which the copolymers according to the invention or the comparative polymers were mixed in solid form. Following the dry blending, a certain amount of water was added and thoroughly stirred using a drill with G3 mixer (duration 2 * 15 seconds). After a maturing time of 5 minutes, the tile adhesive mortar was subjected to a first visual inspection.

Determination of slump

The determination of the slump was carried out after the ripening period and a second time 30 minutes after mixing (after brief stirring by hand) according to DIN 18555, Part 2.

Determination of water retention

The water retention was determined about 15 minutes after mixing according to DIN 18555, Part 7.

Determination of stickiness / ease of movement

The determination of the stickiness or ease of the test mixture is carried out by a qualified person skilled in the art.

Determination of slipping

The slipping was determined about 3 minutes after mixing according to DIN EN 1308. The distance of slipping in mm is given.

Determination of the development time

Deconvolution time was determined by visual inspection by a skilled person with a stopwatch when mixing with a Rilem mixer (Stage I).

Determination of wetting of the tiles

The tile adhesive formulation was applied to a concrete slab according to EN 1323 and after 10 minutes a tile (5 x 5 cm) was placed, which was loaded for 30 seconds with a weight of 2 kg. After another 60 minutes, the tile was removed and the percentage of the tile back still adhered to it was determined.

The composition of the tile adhesive mortar is shown in Table 1. <u> Table 1 </ u> Composition of the test mixture (in% by weight) component Amount (wt%) Cement ¹⁾ 37.50 Quartz sand (0.05 - 0.4 mm) 49,50 Limestone flour ²⁾ 5.50 Dispersion powder ³⁾ 3.50 Cellulose fibers ⁴⁾ 0.50 calcium 2.80 Copolymers / Comparative Examples 0.50 Starch ether ⁵⁾ 0.15 Polyacrylamide ⁶⁾ 0.05 ¹⁾ CEM II 42.5 R
²⁾ Omyacarb 130 AL (Omya, Oftingen, Switzerland)
³⁾ Vinnapas RE 530 Z (Wacker Chemie AG, Munich)
⁴⁾ Arbocel ZZC 500 (J. Rettenmaier & Sons GmbH + Co., Rosenberg)
⁵⁾ Eloset 5400 (Elotex, Sempach, Switzerland)
⁶⁾ Floset 130 U DP (SNSF Floerger, Andrézieux Cedex, France)

The tile adhesive mortar is similar to a C2FTE tile adhesive mortar (according to DIN EN 12004) formulated with 2.80 wt .-% calcium formate as an accelerator.

The test results obtained with the copolymers according to the invention, polymeric mixtures and comparative examples are shown in Table 2. Table 2 Processing properties of an adhesive mortar for ceramic tiles, which has been modified with blends according to the invention and corresponding mixtures according to Comparative Examples. additive Slump (cm) Slump size 30 min (cm) Water retention (%) Stirring time (s) Wetting (%) stickiness Slipping (mm) Air void stability Copolymer 1 18.2 17.2 98.8 15 81 medium 2 medium Copolymer 2 17.2 16.8 98.7 19 82 low 3 Good Copolymer 3 17.6 17.3 98.4 17 82 low 5 Good Copolymer 4 18.2 17.7 98.8 16 80 low 2 very well Copolymer 5 18.8 17.7 98.2 10 89 low 4 very well Copolymer 6 18.0 17.8 98.7 15 85 low 6 very well Copolymer 7 17.2 16.6 98.9 14 90 very low 2 Good Copolymer 8 17.0 16.5 98.5 13 80 very low 2 very well Copolymer 9 17.5 16.8 98.5 13 80 very low 2 very well Polymer mixture 1 17.9 17.8 98.9 14 86 very low 0 very well Polymeric mixture 2 17.6 17.7 99.0 11 88 very low 0 very well Comparative Example 1 19.4 18.4 96.0 8th 78 medium > 20 bad Comparative Example 2 17.5 16.9 97.2 10 80 medium 2 very well Cellulose ether MHPC 30000 ¹⁾ 16.2 16.2 98.6 6 70 very high 8th Good ¹⁾ Mecellose PMC 30 U (S) of the company Samsung Fine Chemicals. Seoul, South Korea Amount of water: 330 g
Adhesive mortar: 1,000 g

The test results in Table 2 show that the copolymers according to the invention have markedly better water retention values, lower tackinesses and markedly reduced toughness when working in the tile adhesive mortar than those according to Comparative Examples 1 and 2. The latter show a considerable slump in the high concentration of soluble calcium ions the water retention. The copolymers of the invention, however, show a particularly good water retention even at the high calcium content. The cellulose ether tested as a comparison imparts good retention of water to the tile adhesive mortar at high calcium loads, but with an undesirably high tack, which is disadvantageous for the processor.

The wetting of the tile with the copolymers according to the invention tends to be better than with the comparative polymers 1 and 2. Striking are the differences between the copolymers according to the invention with regard to the ease of adhesion and tackiness in the processing of the tile adhesive mortar. Especially copolymers 7, 8 and 9 show a markedly low tackiness and a concomitant ease of processing the tile adhesive mortar. The pleasant and simple processability leads to a significant reduction in the effort required when distributing the tile adhesive mortar and to simplify the individual steps. The species according to Comparative Examples 1 and 2 show a significantly lower tack compared to the cellulose ether and improved ease of running - but are inferior to the copolymers of the invention.

In the assessment of slipping according to DIN EN 1308 all copolymers of the invention and comparative polymer 2 are at a similar high level. The best stamina, however, are the polymeric blends that completely prevent slipping. The tile adhesives with the polymeric mixtures also show particularly good smoothness, low tack and excellent water retention.

All copolymers of the invention show a high level of air-entraining stability. Here are the copolymers 4, 5, 6, 8 and 9, each containing the structural unit e), characterized by particularly good air-entraining.

- Gypsum plaster for manual application

For this purpose, they were tested in practice using a ready-to-use formulated dry mixture to which the copolymers according to the invention or the comparison products were admixed in solid form. Following the dry homogenization, the test mixture was added to a defined amount of water within 15 seconds, gently stirred with the trowel and then stirred vigorously with a Rilem mixer (stage I) (duration 60 seconds). Then, the mixture was ripened for 3 minutes, and stirred again under the above conditions for 15 seconds.

Determination of the development time

The deployment time when mixing with a Rilem mixer (Level I) was subjectively determined by a visual expert with a stopwatch.

Determination of water retention

The water retention was determined after the maturation period in accordance with DIN 18555, Part 7.

Determination of air-entrainment stability

The air-pore stability was qualitatively determined by visual assessment.

Determination of stickiness / ease of movement

The determination of the stickiness or ease of the test mixture was carried out by a qualified person skilled in the art.

Determination of stamina

The determination of the stability of a freshly applied 20 mm thick plaster layer after the maturing time was carried out by a qualified person skilled in the art.

Determination of nodule load

The determination of the nodule content took place after the maturation period by visual and manual observation by a qualified person.

The composition of gypsum plaster is shown in Table 3. Table 3: Composition of the test mixture (in% by weight) component Amount (wt%) Calcium sulfate beta hemihydrate 45.0 Crushed lime 5.20 Limestone flour (<0.1 mm) 1.1 Limestone sand (0.1-1 mm) 47.2 Perlite (0-1 mm) 1.1 Copolymers / Comparative Examples 0.3 Air entrainment agent ¹⁾ 0.03 Tartaric acid (retarder) 0.07 ¹⁾ Genapol PF 80p (Clariant GmbH, Frankfurt / Main) Processing properties of a gypsum plaster for manual application, which has been modified with blends according to the invention and corresponding comparative blends. additive nodule count Water retention (%) Stirring time (s) stickiness staying power Air void stability Copolymer 1 low 98.3 20 medium high Good Copolymer 2 low 98.2 24 low high-medium Good Copolymer 3 low 97.4 21 very low medium Good Copolymer 4 low 98.3 21 low high very well Copolymer 5 low 97.6 15 low high-medium very well Copolymer 6 low 98.2 20 low medium very well Copolymer 7 very low 98.3 17 very low high Good Copolymer 8 low 98.0 18 very low high very well Copolymer 9 very low 98.0 18 very low high very well Polymer mixture 1 very low 98.4 19 very low very high very well Polymeric mixture 2 very low 98.6 16 very low very high very well Comparative Example 1 medium 96.1 12 medium low medium Comparative Example 2 low 97.7 13 medium-low high-medium very well Amount of water: 540 g
Dry mortar: 1,000 g

The test results in Table 4 show that the copolymers according to the invention, especially in the assessment criterion stickiness and the associated ease of movement, a significant improvement over the species according to Comparative Examples 1 and 2 could be achieved. Furthermore, the copolymers according to the invention provide good stability. It is possible to apply extremely thick layers of plaster, to process them smoothly, without the plaster mixture falling off the wall. This advantage is illustrated especially with the polymeric mixtures 1 and 2. The water retention properties of the copolymers according to the invention are also higher than those of the species according to Comparative Examples 1 and 2. The pleasant and simple processability leads to a significant reduction in the effort required to apply and distribute the fresh gypsum plaster and to simplify the individual work steps. All copolymers show consistently high levels of air pore stability. Of these, in turn, the copolymers 4, 5, 6, 8 and 9 are particularly characterized, which allow a particularly good air-pore stability and thus improved dispersibility of the plaster mixture.

Claims (24)

1. Copolymer comprising,

   i) 5 to 60 mol% of a structural unit a),

   ii) 20 to 80 mol% of a structural unit b) and

   iii) 0.01 to 3 mol% of a structural unit c),
   the structural unit a) being represented by the following general formula (I):

   

   in which

   R¹ is identical or different and is represented by hydrogen and/or a methyl radical,

   R² and R³ are each identical or different and, independently of one another, are each represented by hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms and/or an aryl radical having 6 to 14 C atoms,

   R⁴ is identical or different and is represented by a substituent identical to R² or R³, - (CH₂)_x-SO₃M_k,

   

   and/or

   

   M is identical or different and is represented by a monovalent or divalent metal cation, ammonium cation and/or quaternary ammonium cation (NR₁R₂R₃R₄)⁺,

   k is identical or different and is represented by ½ and/or 1,

   Y is identical or different and is represented by oxygen, -NH and/or -NR²,

   V is identical or different and is represented by -(CH₂)_x-,

   

   and/or

   

   x is identical or different and is represented by an integer from 1 to 6,

   X is identical or different and is represented by a halogen atom, C₁- to C₄-alkylsulphate and/or C₁- to C₄-alkanesulphonate,

   the structural unit b) being represented by the following general formulae (IIa) and/or (IIb):

   

   in which

   Q is identical or different and is represented by hydrogen and/or -CHR²R⁵,

   R¹, R² and R³ each have the abovementioned meanings, with the proviso that, where Q is not hydrogen, R² and R³ in the general formula (IIb) together may represent a -CH₂-(CH₂)_y-methylene group, so that the general formula (IIb) is present according to the following structure:

   

   where

   R⁵ is identical or different and is represented by a hydrogen atom, a C₁- to C₄-alkyl radical, a carboxyl group and/or a carboxylate group -COOM_k, y being identical or different and being represented by an integer from 1 to 4, and M and k each have the abovementioned meanings,

   the structural unit c) being represented by the general formula (III):

   

   in which

   U is identical or different and is represented by -COO(C_mH_2mO)_n-R⁶, and/or -(CH₂)_p-O(C_mH_2mO)_n-R⁶,

   m is identical or different and is represented by an integer between 2 and 4,

   n is identical or different and is represented by an integer between 1 and 200,

   p is identical or different and is represented by an integer between 0 and 20,

   R⁶ is identical or different and is represented by

   

   R⁷ is identical or different and is represented by hydrogen, a C₁- to C₆-alkyl group and/or an arylalkyl group having a C₁-to C₁₂-alkyl radical and C₆- to C₁₄-aryl radical,

   z is identical or different and is represented by an integer between 1 and 3 and

   R¹ has the abovementioned meaning.
2. Copolymer according to Claim 1, characterized in that the structural unit a) arises from the polymerization of one or more of the monomer species [2-(acryloyloxy)ethyl]trimethylammonium chloride, [2-(acryloylamino)ethyl]trimethylammonium chloride, [2-(acryloyloxy)ethyl]trimethylammonium methosulphate, [2-(methacryloyloxy)ethyl]trimethylammonium chloride or methosulphate, [3-(acryloylamino)propyl]trimethylammonium chloride, [3-(methacryloylamino)propyl]trimethylammonium chloride, N-(3-sulphopropyl)-N-methylacryloyloxyethyl-N',N-dimethylammonium betaine, N-(3-sulphopropyl)-N-methacrylamidopropyl-N,N-dimethylammonium betaine and/or 1-(3-sulphopropyl)-2-vinylpyridinium betaine.
3. Copolymer according to Claim 1 or 2, characterized in that the structural unit b) arises from the polymerization of one or more of the monomer species acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-ethylacrylamide, N-cyclohexylacrylamide, N-benzylacrylamide, N-methylolacrylamide, N-tert-butylacrylamide, etc. Examples of monomers as a basis for the structure (IIb) are N-methyl-N-vinylformamide, N-methyl-N-vinylacetamide, N-Vinylpyrrolidone, N-vinylcaprolactam and/or N-vinylpyrrolidone-5-carboxylic acid.
4. Copolymer according to any of Claims 1 to 3, characterized in that the structural unit c) arises from the polymerization of one or more of the monomer species
   tristyrylphenol polyethylene glycol-1100-methacrylate, tristyrylphenol polyethylene glycol-1100-acrylate, tristyrylphenol polyethylene glycol-1100-monovinyl ether, tristyrylphenol polyethylene glycol-1100 vinyloxybutyl ether and/or tristyrylphenol polyethylene glycol-block-propylene glycol allyl ether.
5. Copolymer according to any of Claims 1 to 4, characterized in that the structural units a) are present in an amount of 15 to 50 mol%, b) in an amount of 30 to 75 mol% and c) in an amount of 0.03 to 1 mol%.
6. Copolymer according to any of Claims 1 to 5, containing up to 5 mol%, preferably 0.05 to 3 mol%, of a structural unit d) which is represented by the general formula (IV):

   

   in which

   Z is identical or different and is represented by -COO(C_mH_2mO)_n-R⁸ and/or - (CH₂)_p-O(C_mH_2mO)_n-R⁸,

   R⁸ is identical or different and is represented by H and/or C₁- to C₄-alkyl and

   R¹, m, n and p have the meanings mentioned in each case above.
7. Copolymer according to Claim 6, characterized in that the structural unit d) arises from the polymerization of one or more of the following monomer species
   allylpolyethylene glycol-(350 to 2000), methylpolyethylene glycol-(350 to 3000) monovinyl ether, polyethylene glycol-(500 to 5000) vinyloxybutyl ether, polyethylene glycol-block-propylene glycol-(500 to 5000) vinyloxybutyl ether, methylpolyethylene glycol-block-propylene glycol allyl ether, methylpolyethylene glycol-750 methacrylate, polyethylene glycol-500 methacrylate, methylpolyethylene glycol-2000 monovinyl ether and/or methylpolyethylene glycol-block-propylene glycol allyl ether.
8. Copolymer according to any of Claims 1 to 7 containing up to 40 mol%, preferably from 0.1 to 30 mol%, of a structural unit e) which is represented by the general formula (V):

   

   in which

   W is identical or different and is represented by -CO-O-(CH₂)_x- and/or -CO-NR²-(CH₂)_x- and

   R¹, R², R³ and x each have the abovementioned meanings.
9. Copolymer according to Claim 8, characterized in that the structural unit e) arises from the polymerization of one or more of the following monomer species
   [3-(methacryloylamino)propyl]dimethylamine, [3-(acryloylamino)propyl]dimethylamine, [2-(methacryloyloxy)ethyl]dimethylamine, [2-(acryloyloxy)ethyl]dimethylamine, [2-(methacryloyloxy)ethyl]diethylamine and/or [2-(acryloyloxy)ethyl]diethylamine.
10. Copolymer according to any of Claims 1 to 9, containing up to 20 mol%, preferably 0.1 to 10 mol%, of a structural unit f) which is represented by the general formula (VI):

    

    in which

    S is identical or different and is represented by -COOM_k and

    M, k and R¹ each have the abovementioned meanings.
11. Copolymer according to Claim 10, characterized in that the structural unit f) arises from the polymerization of one or more of the following monomer species acrylic acid, sodium acrylate, methacrylic acid and/or sodium methacrylate.
12. Copolymer according to any of Claims 1 to 11, having a number average molecular weight of 50 000 to 20 000 000.
13. Copolymer according to any of Claims 1 to 12, which has branched and/or crosslinked regions.
14. Process for the preparation of a copolymer according to any of Claims 1 to 13 by free radical polymerization in the aqueous phase, by free radical polymerization in inverse emulsion or by free radical polymerization in inverse suspension.
15. Process according to Claim 14, characterized in that the free radical polymerization is effected as a gel polymerization in the aqueous phase.
16. Process according to Claim 14 or 15, characterized in that the free radical polymerization is effected in the presence of a crosslinking agent.
17. Use of a copolymer according to any of Claims 1 to 16 as an admixture for aqueous building material systems which contain hydraulic binders, in particular cement, lime, gypsum or anhydrite.
18. Use according to Claim 17, characterized in that the hydraulic binder is present as a dry mortar composition, in particular as tile adhesive or gypsum plaster.
19. Use according to Claim 17 or 18, which is effected in combination with non-ionic polysaccharide derivatives.
20. Polymeric mixture containing

    α) a copolymer according to any of Claims 1 to 13 and

    β) an anionic surfactant which is represented by the general formulae
    
            (VII)     J-K
    
    or
    
            (VIII)     T-B-K,
    
    J and T each representing the hydrophobic part of the surfactant, K being an anionic functional group, T representing a hydrophobic part of the surfactant and B being a spacer group,

    J being represented by an aliphatic hydrocarbon radical having 8 to 30 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms or an aryl radical having 6 to 14 C atoms,

    K being represented by -SO₃M_k, -OSO₃M_k, -COOM_k, or -OP(O)(OH)OM_k,

    M and k each having the abovementioned meaning,

    T being represented by an aliphatic hydrocarbon radical having 8 to 30 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an aryl radical having 6 to 14 C atoms or R⁶,

    B being represented by -O(C_mH_2mO)_n- and

    K, R⁶, m and n each having the abovementioned meanings.
21. Polymeric mixture according to Claim 20, comprising 80 to 99% by weight of the copolymer and 1 to 20% by weight of the anionic surfactant.
22. Polymeric mixture according to Claim 20 or 21, characterized in that the anionic surfactant according to the general formula (VII) is present as alkanesulphonate, arylsulphonate, alpha-olefinsulphonate or alklyphosphate or as a fatty acid salt, and the anionic surfactant of the general formula (VIII) as alkyl ether sulphate.
23. Use of a polymeric mixture according to any of Claims 20 to 22 as an admixture for aqueous building material systems which contain hydraulic binders.
24. Use according to Claim 22, which is effected in combination with non-ionic polysaccharide derivatives.